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-   -   buoyantBoussinesqSimpleFoam - continuity error (http://www.cfd-online.com/Forums/openfoam-solving/95808-buoyantboussinesqsimplefoam-continuity-error.html)

vitors January 3, 2012 15:37

buoyantBoussinesqSimpleFoam - continuity error
 
Hello all,

I am new to OpenFoam and I'm trying to solve a simple (at last I think it is...) case in which I have a heated rod inside a pipe. For natural convection it seems ok.

When I try to start a flow (inlet and outlet flows) I get a "continuity error message".

I based the configuration files on "hotRoom" OpenFoam's tutorial case.

The boundary conditions are:

p: inlet -> zeroGradient
outlet -> FixedValue uniform 0;
insideWall -> zeroGradient;
outsideWall -> zeroGradient;

U: inlet -> FixedValue (0 1 0)
outlet -> ZeroGradient (or calculated $internalField;
insideWall -> FixedValue (0 0 0);
outsideWall -> FixedValue (0 0 0);

T: inlet -> FixedValue 300;
outlet -> zeroGradient (or calculated $internalField);
insideWall -> FixedValue 1000;
outsideWall -> FixedValue 300;

So, any suggestions?
Thanks in advance.

Vitor

romant January 4, 2012 05:00

Quote:

Originally Posted by vitors (Post 337714)
Hello all,

I am new to OpenFoam and I'm trying to solve a simple (at last I think it is...) case in which I have a heated rod inside a pipe. For natural convection it seems ok.

When I try to start a flow (inlet and outlet flows) I get a "continuity error message".

I based the configuration files on "hotRoom" OpenFoam's tutorial case.

The boundary conditions are:

p: inlet -> zeroGradient
outlet -> FixedValue uniform 0;
insideWall -> zeroGradient;
outsideWall -> zeroGradient;

U: inlet -> FixedValue (0 1 0)
outlet -> ZeroGradient (or calculated $internalField;
insideWall -> FixedValue (0 0 0);
outsideWall -> FixedValue (0 0 0);

T: inlet -> FixedValue 300;
outlet -> zeroGradient (or calculated $internalField);
insideWall -> FixedValue 1000;
outsideWall -> FixedValue 300;

So, any suggestions?
Thanks in advance.

Vitor

For your pressure, you should set the boundary condition to buoyantPressure

for the outlet velocity condition try pressureInletOutletVelocity with value (0 0 0).

greel January 4, 2012 10:02

I always use this bc in p_rgh

wall
{
type buoyantPressure;
rho rhok;
value uniform 0;
}

outlet
{
type zeroGradient;
}
inlet
{
type fixedValue;
value uniform 0;
}

vitors January 12, 2012 10:14

Thanks guys. I got a better result, though not perfect. But with this buoyantPressure BC I'll try to tune my simulation.

ameyadurve September 21, 2012 04:55

Divergence problem solved by Greel's suggestion
 
@ Greel:

Boundary conditions for p_rgh suggested by you worked for my simulation.

I was having a divergence problem for buoyantBoussinesqSimpleFoam that got solved with those boundary conditions.

How good the results are, remains to be seen.

Thanks a lot
Ameya

Kanarya April 29, 2015 16:25

How was the results?
I have similar doubts about p and p_rgh boundary conditions in buoyantBoussinesqSimpleFoam solver applied in simple pipe simulation...

thanks!
Quote:

Originally Posted by ameyadurve (Post 382931)
@ Greel:

Boundary conditions for p_rgh suggested by you worked for my simulation.

I was having a divergence problem for buoyantBoussinesqSimpleFoam that got solved with those boundary conditions.

How good the results are, remains to be seen.

Thanks a lot
Ameya



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